Herbicidal use of unsaturated esters of dithiocarbazic acids



United States Patent 3,244,501 HERBICIDAL USE OF UNSATURATED ESTERS 0F DITHIOCARBAZIC ACIDS John J. DAmico, Charleston, W. Va., assiguor to Monsanto Company, a corporation of Delaware No Drawing. Original application July 25, 1962, Ser. No. 212,450. Divided and this application Dec. 18, 1963, Ser. No. 338,547

9 Claims. (Cl. 712.3)

This application is a division of my copending application 212,450 filed July 25, 1962.

This invention relates to new chemical compositions of matter. More particularly, this invention relates to esters of dithiocarbazic acids of the genenal formula 8 11 ll NNCSR" where R is hydrogen, lower alkyl or hydroxylalkyl, R is hydrogen or lower alkyl and R" is lower alkenyl, halogenated lower alkenyl or cyclohexenyl. Typical examples of R" comprise cisand trans-2,3-dichloro2-butenyl, 3- chloro-2-butenyl, 2-chloroallyl, Z-bromoallyl, 3-chloroallyl, cisand trans-2,3-dichloroallyl, 3-iodoallyl, 3-iodo-2- butenyl, 2,3-diodo-2-butenyl, 2-fiuoro-3-chloroallyl, allyl, 2-butenyl, 4-chloro-2-butenyl, 3,3-dichloroallyl, 2-iodoallyl, 3-bromoallyl, 2,3-dibromoallyl and 2,3,3-trichloroallyl. When R" is cyclohexenyl, the 2-cyclohexenyl radical is preferred but isomers thereof and middle halogen as well as lower alkyl substituted derivatives are contemplated. Examples are 3-cyclohexenyl, 4-bromo-2-cyclohexenyl, 2-chloro-2-cyclohexenyl, 3-chloro-2 cyclohexenyl, 2-bromo-3-cyclohexenyl, 2-methyl-2 cyclohexenyl, 3-'methyl-2-cyclohexenyl, 4-methyl-2 cyclohexenyl, 5- methyl-2-cyclohexe nyl and 2-ethyl-2-cyclohexenyl.

The compounds are prepared most conveniently by condensing an alkali metal, ammonium or amine salt of the corresponding dithiocarbazic acid with a chloride or bromide containing the desired unsaturated ester radical. The lower ralkenyl esters readily add halogen across the double bond and by successive halogenation and dehydrohalogenation the halogenated lower alkenyl esters can be prepared. However, it is generally more satisfactory to prepare the halogenated lower alkenyl chloride or bromide in a separate operation. The hydrogen on the nitrogen in the 2-position is somewhat basic and undergoes reaction with acidic condensing agents as for example, acetyl chloride and aldehydes, preferably formaldehyde. The thiocarbonyl radical under the influence of silver oxide is converted to the carbonyl radical. In the presence of oxygen catalyst the compounds undergo polymerization to form useful resins. A preferred class of resins are produced by condensing one mole of the carbazate with about one-half mole of formaldehyde and subjecting the resulting product to the action of oxygen catalysts including peroxides like benzoyl peroxide. The polymers vary from soluble fusible products to insoluble infusible resins depending upon the duration of the reaction.

Most of the compounds possess biological activity and find direct use in the industrial arts. It should be understood that all compounds of the aforesaid formula are by no means equivalent and the biological properties vary widely depending upon the substituent radicals R, R and R". Compounds in which R and R are hydrogen and R" is lower 2-alkenyl, monoor dihalogenated lower 2- alkenyl or cyclohexenyl are contact herbicides some of which are also effective as pre-emergence herbicides. Allyl and 2,3-dichloroallyl esters of substituted dithiocarbazic acids where R and R are lower alkyl or R is hydrogen and R is 2-hydroxyethyl are pre-emergent grass herbicides. On the other hand, 2-chloroallyl esters of 3,

ice

3-di-lower alkyldithiocarbazic acids are useful foliage contact herbicides for control of broadleaf weeds. Other kinds of biological activity are hereinafter illustrated.

For the purpose of describing the invention and not as limitative thereof, the following examples are given:

Example 1 A solution comprising 33.8 grams (1.0 mole) of hydrazine, 400 ml. of ethyl alcohol and grams of concentrated ammonium hydroxide was prepared and 76 grams (1.0 mole) of carbon bisulfide added dropwise at 0-10 C. After stirring at 010 C. for 30 minutes, 76.6 grams (1.0 mole) of allyl chloride was added dropwise while maintaining the temperature at 010 C. The reaction mixture was stirred at 25-30 C. for 48 hours, then 400 ml. of water and 500 ml. of ethyl ether were added. The ether solution was separated, washed with water until neutral to litmus and dried over sodium sulfate. The ether was removed in vacuo at a maximum temperature of 8090 C./12 mm. Allyl dithiocarbazate was obtained in 37% yield as an amber oil. Analysis gave 18.86% nitrogen compared to 18.90% calculated for C H N S Example 2 To a stirred solution containing 20 grams (0.53 mole) of 85% hydrazine, 85 grams (0.53 mole) of 25% sodium hydroxide and 300 ml. of water was added dropwise at 10 15 C., 40.4 grams (0.53 mole) of carbon bisulfide. EX- ternal cooling was removed and the stirred reaction mixture held at 2530 C. for an hour. Then 80.5 grams 0.5 mole) of 3-bromocyclohexene was added in one portion. The reaction mixture was stirred at 25-30 for 24 hours and then extracted with 500 ml. of ethyl ether. The ether solution was washed with water until neutral to lit-mus, dried over sodium sulfate and the ether removed in vacuo at a maximum temperature of 2530 C. The Z-cyclohexenyl dithiocarbazate was obtained in 61.5% yield as a tan solid. It melted at -157 C. after recrystallization from ethyl alcohol. Analysis gave 14.83% nitrogen as compared to 14.87% calculated for C H N S Example 3 A solution comprising 30 grams (0.5 mole) of dimethyl hydrazine, 50 grams of concentrated ammonium hydroxide and 200 ml. of ethyl alcohol was prepared and 38 grams (0.5 mole) of carbon bisulfide added dropwise at 520 C. After stirring at 2530 C. for one hour, 38.3 grams (0.5 mole) of allyl chloride was added in one portion. The reaction mixture was stirred at 25-30 C. for 24 hours and then 300 ml. of Water and 400 ml. of ethyl ether added. The ether solution was washed with water until neutral to litmus, dried over sodium sulfate and the ether removed in vacuo. The product was dried on a porous plate. After recrystallization from heptane the allyl 3,3-dimethyldithiocarbazate melted at 6768 C. It was obtained in 63.6% yield as a yellow solid analyzing 16.39% nitrogen and 36.28% sulfur compared to 15.89% nitrogen and 36.38% sulfur calculated for C H N S Example 4 To a stirred solution containing 30 grams (0.5 mole) of dimethyl hydrazine, 50 grams of concentrated ammonium hydroxide and 200 ml. of ethyl alcohol was added dropwise at 5-15 C., 38 grams (0.5 mole) of carbon bisulfide and the mixture stirred at 2530 C. for one hour. After cooling to 5 C., 62.5 grams (0.5 mole) of 1,3-dichloro-2-butene was added at 5-20" C. and stirring continued at 25-30 C. for 24 hours. Thereupon 350 ml. of water was added, the mixture cooled to 5 C., filtered, washed with cold water (500 ml.) and air-dried at 2530 C. 3-chloro-2-butenyl 3,3 dimethyldithio- 3 carbazate was obtained as a yellow solid in 76.7% yield. After recrystallization from heptane it melted at 83-84 C. Analysis gave 28.60% sulfur compared to 28.53% calculated for C H CIN S hours, 300 ml. of Water added and the stirred reaction mixture cooled to C. The resulting precipitate was collected by filtration, washed with water until neutral to litmus and air-dried at 25-30 C. 2,3,3-trichloroallyl Example 5 5 3,3-diethyldithiocarbazate was obtained in 84.5% yield as a tan solid melting at 7980 C. after recrystallization To a Solutlon coPtalmng grams mole) from ethyl alcohol. Analysis gave 21.54% sulfur and 0f Yf Y l llydralme, 50 grams of Concentrated 34.47% chlorine compared to 20.84% sulfur and 34.60% ammonium hydroxide and 300 ml. of ethyl alcohol was chlorine calculated f C8HI3C13N2S2 added dT 0PW13e at Q, 38 grams mole) of 10 The yield and physical properties of further examples carbon bisulfide and the mixture stirred at O10 C. for f the invention d i a manner i il to h d Q n 0 30 mlnlltes- Aftfil (30011115 to 0 y mefins of an scribed in the preceding examples are recorded in the folbath, 38.3 grams (0.5 mole) of allyl chloride was added lowing table; dropwise at 0l0 C. and the reaction mixture was stirred TABLE I at 25-30" C. for 48 hours. Thereupon 400 ml. of water and 500 ml. of ethyl ether were added and stirring con- Compound Yield Physical tinned for 15 minutes. The ether solution was washed percent Appearance with water until neutral to litmus, dried over sodium sull fate and the ether removed in vacuo at a maximum tem- 2-cliloroall l dithiocarbazate 89. 5 Amber 011. perature of 30 C./1-2 min. Allyl 3-(2-hydroxyethyl) cisalllld trtns-2,3-dichloroally1dithio- 69.2 Do.

- ear azate. d thiocarbazate was obtained in 79.3% yield as an amber 2 bmm0auy1 dithj0carbmte 57 2 011. It was insoluble in water and heptane but soluble g1,3igichl fioiilyghdithi%:arbtazate 33.5 A gin. 1d -e oroa y i ioear aza e ...4 m er semi-sci in ether, acetone, benzene and ethanol. Analysis gave 3 ch1or0 buteny1dithiocarbazate 620 Amber on. 14.50% nitrogen and 33.86% sulfur compared to 14.57% 3,3-dighloit oallyl 3,3-dii'nethyldithi0- sso Do. nitrogen and 33.35% sulfur calculated for C H N OS ggf f g i g 836 Do zate. Example 5 eis-an ig -asd ehi wau iaadi- 60.4 Do. met 1 ioear aza e. To a stirred slurry of 6.7 grams (0.2 mole) of 95% cis-agd tranffligdighloroillyl3-(2- 73.6 Do.

- hy roxyet iy it iiocar azate. hydrazme ,grams male) of Concentrated am 2,3,3tricliloroallyl 3,3-dipropyldithio- 92.0 Do. moninm hydroxide and 200 ml. of ethyl alcohol was Afiaiibgagaml m h I t 889 D o y iet 1y it iocar )aza e 0. added P at 5 15 f grams of cis and trans-2,3-dic11l0roallyl3,3- 82.0 Do. carbon bisulfide. After stirring the mixture at 2530 C. diethyldithiocarbazat e. for an hour, 36 grams (0.2 mole) of 1,1,2,3-tetrachloro-1- figggl f propene was added in one portion, causing the tempera- 2-chloroal1yl3,3-diethylditliiocarbazate 64.9 w l7lgfit7b7s Ogcl, m.p.

a true to rise from 26 to 36 C. Stirring was continued at 3; 3 Cmom 2 buteny1 ayamfimmuhw I 750 Amber on 2530 C. for 24 hours whereupon 300 ml. of water and carbazate- 300 ml. of ethyl ether were added and stirring continued g'bromoanyl 3g'dlethyldlthlocarbame"- giglii for 25 minutes longer. The ether layer was washed with 3-cliloroallyl 3,3'diethylditliiocarbazate 35.6 Tan solid, m.p.

- o a a 0 water until neutral to litmus and dried over sodium sul- 84 85 fate. The ether was removed in vacuo at a maximum 40 a after recrvqmuimionfmm heptane te'mljerature of 80-90u 2 i y b after recrystallization from ethyl alcohol. dithiocarbazate was obtained in 57.7% yieldv as a dark amber oil. It was insoluble in water, slightly soluble in I A Indicated, the n compounds possess biological achot heptane but soluble :in ether, acetone, benzene and l some are efifacnve for destroymfg undeslrefi Vega ethanOL tation, the most important of which contain the Example 7 H NNH radical, while others are useful for combatting plant diseases and, microorganisms. As illustrative A solution comprising 17.7 grams (0.2 mole) of diethyl of herbicidal activity a spray containing various concenhydrazine, 20 grams of concentrated ammonium hydroxtrations of the active ingredient shown in Table II was ide and 100 ml. of ethyl alcohol was prepared and 15.2 applied to the foliage of a mixture of grasses, to the grams (0.2 mole) of carbon bisulfide added dropwise at foliage of bean plants and finally to the foliage of a 515 C. After stirring at 2530 C. for an hour, 36 mixture of broadleaved plants. The mixture is indicated grams (0.2 mole) of 1,1,2,3-tetrachloro-l-propene was in the table as Broadleaf. A rating of 0 indicates no added causing the temperature to rise from 25 to C. phytotoxicity, l slight, 2 moderate, 3 severe phytotoxicity, T he reaction mixture was stirred at 2530 C. for 24 55 4plants dead andB defoliation.

TABLE II Phytotoxicity Rating Percent Active Ingredient Cone.

Grass Bean Broadleat Allyl dithioearbazate g f Z-ehloroallyl (lithiocarbazate g i? 3-cliloroallyl ditliiocarbazate 0.5 1 1 2 cisand trans2,3-dicl1loroallyl dithiocarbazate. f 1 2-bromoallyl dithiocarbazate 0. 5 2 2 2B 2 3,3-dicliloroallyl dithioearbazate. 0.5 2 2 3 3-ohlor0-2-butyl dithioearbazate g g 2-cycloliexenyl ditliiocarhaznte 0.5 1 1 3 2-ehlorallyl3,3-dimethylditliiocarbazate 0.5 0 0 3 2-ehloroallyl 3,3-dietliyldithiocarbazate 0.5 O 2 1 defoliation.

Table III illustrates pro-emergence herbicidal activity. The ester was emulsified in water and the emulsion ap plied as a spray. In this manner, the active ingredient at a dosage of 25 pounds per acre was applied to the ground of seeded plots before the grass or other plants emerged:

TABLE III Active Ingredient Results Observed Allyl dithiocarbazate Severe phytotoxicity to rye grass and 3,3-dichloroa11yl dithiocarbazate.

3-chloro-2-bntenyl dithiocarbazate.

2-cycl0hexenyl dithiocarbazate.

cisand trans-2,3-dichloroallyl 3-(2hydroxyethyl)- dithiocarbazate.

cisand trans-2,3-dichloroallyl 3,3-dimethyldithiocarbazate.

Allyl 3(2hydroxyethyl)- dithiocarbazate.

Severe phytotoxicity to barnyard grass.

Severe phytotoxicity to wild oats, wild buckwheat and tomato; moderate phytgotoxicity to morning glory and sugar eet.

Severe phytotoxicity to rye grass; mod erate phytotoxicity to a mixture of grasses, foxtail and sorghum.

cisand trans-2,3,dich1oroallyl 3,3-diethyldithiocarbazate.

Bacteriostatic activity was demonstrated against Micrococcus pyogenes var. aureus and Salmonella typhosa. Each of the test compounds were dissolved in a non-toxic solvent to give respective 1% stock solutions. The stock solutions were then added to nutrient agar in a quantity to give 1 part of product per 1,000 parts of agar. After thorough mixing, the agar was poured into Petri dishes and allowed to harden. One drop of a cell suspension of the bacteria served as inoculum for each plate. The inoculated plates were incubated for 2 days at a temperature of 37 C. At the end of that time inspection of the plates showed complete inhibition of growth of both the M. pyogenes var. areus and S. lyphosa employing the following test compounds:

2,3,3-trichloral1yl 3,3-diethyldithiocarbazate 2,3,3-trichloroallyl 3,3-dipropyldithiocarbazate allyl 3,3-diethyldithiocarbazate cisand trans-2,3-dichloroallyl 3,3-diethyldithiocarbazate 2-chloroailyl 3,3-diethyldithiocarbazate 3-chloro-2-butenyl 3,3-diethyldithiocarbazate 2-bromoallyl 3,3-diethyldithiocarbazate 3-chloroallyl 3,3-diethyldithiocarbazate cisand trans-2,3-dicl1loroallyl 3-(2-hydroxyethyl)-dithiocarbazate 3,3-dichloroallyl 3,3-diethyldithiocarbazate cisand trans-2,3-dichloroallyl dithiocarbazate.

Fungistatic activity was demonstrated against Aspergillus niger. In this test, the test chemicals were mixed in predetermined concentrations with hot dextrose agar which was subsequently poured into Petri dishes, cooled and allowed to harden. The nutrient agar containing the test compound was then inoculated with the fungus organism and the samples incubated for 5 days at 25 C. Growth of the fungus was suppressed by the following compounds at a concentration of 1 part of the dithiocarbazate per 10,000 parts of the agar:

cisand trans-2,3-dichloroallyl 3,3-dimethyldithiocarbazate 3,3-dichloroallyl 3,3-dimethyldithiocarbazate 6 cisand trans-2,3-dichloroallyl 3-(2-hydroxyethyl)dithiocarbazate.

Complete inhibition of the growth of this test fungus using one part of dithiocarbazate per 100,000 parts of agar was obtained with cisand trans-2,3-dichloroallyl dithiocarbazate.

2,3,3-trichloroallyl dithiocarbazate was quite effective as a fungicide. For example, an aqueous suspension containing 0.03% of this compound and a wetting agent was effective in suppressing disease of tomato leaves inoculated with early blight (A lternaria solani). Emulsions containing 0.01% of cisand trans-2,3-dichloroallyl 3,3-diethyldithiocarbazate, Z-bromoallyl 3,3-diethyldithiocarbazate and 3-chloroallyl 3,3-diethyldithiocarbazate applied to tomato plants were effective in preventing tomato late blight (Phytophthora infestans). At a concentration of 1250 parts per million on cucumber plants 3-chloro-2- butenyl 3,3-dimethy1dithiocarbazate controlled Colletotrichum lagenarium, the causative agent of cucumber anthracnose. Fair control of the same organism on cucumber plants was observed with 312 parts per million of cisand trans-2,3-dichloroallyl 3-(2-hydroxyethyl)dithiocarbazate.

Allyl dithiocarbazate, cisand trans-2,3-dichloroallyl dithiocarbazate and 3,3-dichloroallyl dithiocarbazate were etfective as wheat rust eradicants at a concentration of 0.1%. In a few instances insecticidal properties were observed. At a concentration of 0.001% of the active ingredient, kill of the yellow fever mosquito larvae was noted with 3-chloroallyl dithiocarbazate, Z-bromoallyl dithiocarbazate, 3,3-dichloroa1lyl dithiocarbazate and 3,3-dichloroal1yl dimethyldithiocarbazate.

It is intended to cover all changes and modifications of the examples of the invention herein chosen for purposes of disclosure which do not constitute departure from the spirit and scope of the invention.

What is claimed is:

1. The method of destroying undesired vegetation which comprises applying thereto a phytotoxic amount of a composition containing as an essential active ingredient a compound of the formula where R is selected from a group consisting of lower alkenyl, monohalo lower alkenyl, dihalo lower alkenyl and cyclohexenyl.

2. The method of destroying undesired vegetation which comprises applying thereto a phytotoxic amount of a composition containing as an essential active ingredient, allyl dithiocarbazate.

3. The method of destroying undesired vegetation which comprises applying thereto a phytotoxic amount of a composition containing as an essential active ingredient, 2-chloroallyl dithiocarbazate.

4. The method of destroying undesired vegetation which comprises applying thereto a phytoxic amount of a composition containing as an essential active ingredient, 3-chloroallyl dithiocarbazate.

5. The method of destroying undesired vegetation which comprises applying thereto a phytoxic amount of a composition containing as an essential active ingredient, cisand trans-2,3-dichloroallyl dithiocarbazate.

6. The method of destroying undesired vegetation which comprises applying thereto a phytoxic amount of a composition containing as an essential active ingredient, 2-bromoallyl dithiocarbazate.

7. The method of destroying undesired vegetation which comprises applying thereto a phytoxic amount of a cor position containing as an essential active ingredient, 3,3-dichloroallyl dithiocarbazate.

7 8 8. The method of destroying undesired vegetation which References Cited by the Examiner comprises applying thereto a phytoxic amount of a com- UNITED STATES PATENTS position containing as an essential active ingredient,

3-ch1oro-2-butenyl dithiocarbazate. gigg i g 7 2 9. The method of destroying undesired vegetation which 5 2997382 8/1961 Harman i comprises applying thereto a phytoxic amount of a comn position containing as an essential active ingredient, LEWIS GOTTS, Primary i 2-cyclohexenyl dithiocarbazate. ALBERT J. ADAMCIK, Assistant Examiner. 

1. THE METHOD OF DESTROYING UNDESIRED VEGETATION WHICH COMPRISES APPLYING THERETO A PHYTOTOXIC AMOUNT OF A COMPOSITON CONTAINING AS AN ESSENTIAL ACTIVE INGREDIENT A COMPOUND OF THE FORMULA 